Oral hypoglycemic agents

The role of sulfonylureas in the treatment of type 2 diabetes

INTRODUCTION

Type 2 diabetes (T2D) is increasingly prevalent and associated with increased risk for cardiovascular and renal disease. After lifestyle modification, metformin is usually the first-line pharmacotherapy and sulfonylureas are traditionally added after metformin failure. However, with newer glucose lowering drugs that may have less risk of hypoglycemia or that may reduce cardiovascular and renal events, the position of sulfonylureas is being reevaluated.

AREAS COVERED

In this article, the authors review relevant publications related to the use of sulfonylureas.

EXPERT OPINION

Sulfonylureas are potent glucose lowering drugs. The risk of hypoglycemia varies with different drugs within the class and can be minimized by using the safer drugs, possibly in lower doses. Cardiovascular events do not appear to be increased with some of the newer generation drugs. The durability of glycemic control also appears comparable to other newer agents. Sulfonylureas are the preferred treatment for some types of monogenic diabetes and selection of T2D patients who may have greater benefit from sulfonylureas based on certain phenotypes and genotypes is likely to be refined further by precision medicine. Sulfonylureas are inexpensive and readily available everywhere and they are still the most frequently used second-line treatment for T2D in many parts of the world.

Antihyperlipidemic effect of tyrosol, a phenolic compound in streptozotocin-induced diabetic rats

We investigated the antihyperlipidemic effects of tyrosol in streptozotocin (STZ)-induced diabetic rats. Rats were injected intraperitoneally with STZ (40 mg/kg), and these established experimental rats were treated with tyrosol (20 mg/kg) and glibenclamide (600 µg/kg) for 45 days. The observed results revealed that tyrosol treatment significantly reduced plasma glucose, plasma, and liver total cholesterol, triglycerides, free fatty acids, phospholipids, plasma low-density lipoprotein cholesterol, very low-density lipoprotein cholesterol, atherogenic index, and significantly increased plasma insulin and high-density lipoprotein cholesterol in STZ-induced diabetic rats. The activity of 3-hydroxy 3-methylglutaryl coenzyme A reductase significantly reduced in the liver, whereas the activities of lipoprotein lipase and lecithin cholesterol acyltransferase were significantly increased in the plasma of tyrosol treated STZ-induced diabetic rats. Histological examination showed that tyrosol treatment remarkably reduced lipid accumulation in the liver of STZ-induced diabetic rats. The present study revealed that tyrosol exhibits potent antihyperlipidemic effects in STZ-induced diabetic rats.

The Chinese herbal formulae (Yitangkang) exerts an antidiabetic effect through the regulation of substance metabolism and energy metabolism in type 2 diabetic rats

ETHNOPHARMACOLOGICAL RELEVANCE

Type 2 diabetes mellitus (T2DM) regarded as a "hot" disease in traditional Chinese medicine (TCM). Accordingly, TCM uses a cold drug or formula such as the Chinese herbal formulae "Yitangkang" (YTK) as a treatment. YTK exhibited a good clinical antidiabetic effect in several experiments. The correlation between the properties of a TCM drug or formula and its ability to regulate the substance metabolism, the energy metabolism and the endocrine system has been proven.

AIM OF THE STUDY

The present study aiming to evaluate the mechanism of antidiabetic action of YTK from the above perspective.

MATERIALS AND METHODS

Three groups of streptozotocin (STZ)-diabetic rats have been treated with YTK at oral doses of 56 g/kg/d, 28 g/kg/d and 14 g/kg/d for 28 days using metformin as a reference drug. After treatment, several indices correlated with energy metabolism (superoxide dismutase, glutathione peroxidase, lactic dehydrogenase, adenotriphos, creatine phosphate kinase, AMPK, Na⁺-K⁺-ATPase and Respiratory Chain Complex I, II, III, IV), substance metabolism (hepatic glycogen, acetyl-coenzyme A, pyruvic acid, adipose triglyceride lipase, triglycerides, high-density lipoproteins, low-density lipoproteins, malonyldialdehyde), endocrine system (triiodothyronine, thyroxine, 17-hydroxycorticosteroid) and cyclic nucleotide system (cyclic adenosine monophosphate, cyclic guanosine monophosphate) have been determined. The specialty and tendency of YTK's effects were analyzed to elucidate its property and mechanism of action according to the theory of TCM.

RESULTS

Our findings showed that the formulae YTK could effectively regulate the levels of blood glucose, HbA1c, glucagon-like peptide-1, and significantly down-regulate the substance metabolism, energy metabolism and endocrine system indices of the diabetic rats.

CONCLUSION

These results were consistent with the TCM description of YTK as a "cold" treatment. It could provide an effective way to interpret the scientific connotation and comprehensive system of the Chinese herbal formulae.

QT prolongation caused by insulin-induced hypoglycaemia - An interventional study in 119 individuals

AIMS

Hypoglycaemia is associated with increased risk of cardiovascular events and mortality in patients with diabetes, but the extent and mechanisms of this link are ill defined. We here prospectively studied cardiac repolarization abnormalities during insulin-induced hypoglycaemia in humans.

METHODS

119 individuals (69 males, age 47.5±13.4years, range 18-82years) were assessed during hypoglycaemia after the injection of 0.1-0.25units/kg human insulin. Corrected QT intervals (QTc) and QT dispersion (QTd) were calculated from serially recorded twelve lead electrocardiograms, and plasma glucose and other endocrine markers were studied.

RESULTS

QTc increased from 415.1±21.9ms (mean±standard deviation) at baseline to 444.9±26.5ms during hypoglycaemia (plasma glucose nadir, 1.6±0.5mmol/L, p=0.001), accompanied by an increase of QTd from 45.0±22.7ms to 64.1±40.0ms (p<0.001). Hypoglycaemia-induced abnormal QTc prolongation (defined as ⩾460ms in females and ⩾450ms in males) occurred in 17% (9/54) of females and 26% (17/65) of males. 97 of 119 of individuals (82%) developed transient hypokalaemia (K⁺ ⩽3.6mmol/L), and plasma epinephrine increased from 220.4±169.5pmol/L at baseline to 2945.6±2421.4pmol/L during hypoglycaemia. Baseline QTc, but not age or gender, was a significant predictor of hypoglycaemia-induced QTc prolongation (p=0.001).

CONCLUSIONS

Insulin-induced hypoglycaemia frequently causes abnormal QT prolongation and is associated with hypokalaemia and sympathoadrenal activation, thereby increasing the potential risk for ventricular arrhythmias, particularly in individuals with pre-existing high normal QTc.

HYPERGLYCEMIA MANAGEMENT IN PATIENTS WITH POSTTRANSPLANTATION DIABETES

OBJECTIVE

Posttransplantation diabetes (PTDM) is a common occurrence after solid-organ transplantation and is associated with increased morbidity, mortality, and health care costs. There is a limited number of studies addressing strategies for hyperglycemia management in this population, with a few articles emerging recently.

METHODS

We performed a PubMed search of studies published in English addressing hyperglycemia management of PTDM/new-onset diabetes after transplant (NODAT). Relevant cited articles were also retrieved.

RESULTS

Most of the 25 publications eligible for review were retrospective studies. Insulin therapy during the early posttransplantation period showed promise in preventing PTDM development. Thiazolidinediones have been mostly shown to exert glycemic control in retrospective studies, at the expense of weight gain and fluid retention. Evidence with metformin, sulfonylureas, and meglitinides is very limited. Incretins have shown promising results in small prospective studies using sitagliptin, linaglitpin, and vildagliptin and a case series using liraglutide.

CONCLUSION

Prospective randomized studies assessing the management of hyperglycemia in PTDM are urgently needed. In the meantime, clinicians need to be aware of the high risk of PTDM and associated complications and current concepts in management.

Hypoglycemia Secondary to Sulfonylurea Ingestion in a Patient with End Stage Renal Disease: Results from a 72-Hour Fast

Insulin, proinsulin, and C-peptide levels increase with sulfonylurea exposure but the acuity of increase has not been described in dialysis patients. We present a case of a dialysis patient who presented with hypoglycemia and was found to have accidental sulfonylurea ingestion. This is a 73-year-old man with ESRD on peritoneal dialysis, without history of diabetes, who presented with hypoglycemia. Past medical history includes multiple myeloma, congestive heart failure, and hypertension. At initial presentation, his blood glucose was 47 mg/dL, with concomitant elevations in the following: C-peptide 30.5 (nl: 0.8-3.5 ng/mL), insulin 76 (nl: 3-19 μIU/mL), and proinsulin 83.3 (nl: ≤8.0 pmol/L). During the 72-hour fast, which he completed without hypoglycemia, insulin declined to be within normal limits (to 12 μIU/mL); proinsulin (to 12.1 pmol/L) and C-peptide (to 7.2 ng/mL) levels decreased but remained elevated. The sulfonylurea screen ultimately returned positive for glipizide, clinching the diagnosis. This is the first reported case which characterizes the chronic elevation of proinsulin in a patient with ESRD, as well as its dramatic increase after a presumed solitary exposure to sulfonylurea. The 72-hour fast conducted gives insight into the clearance of insulin, proinsulin, and C-peptide after sulfonylurea ingestion in ESRD.

WITHDRAWN: Sulphonylurea monotherapy for patients with type 2 diabetes mellitus

The Cochrane Metabolic and Endocrine Disorders Group withdrew this review as of Issue 7, 2015 because of the involvement of one author (SS Lund) being employed in a pharmaceutical company. The authors of the review and the Cochrane Metabolic and Endocrine Disorders Group did not find that this was a breach of the rules of the Cochrane Collaboration at the time when it was published. However, after the publication of the review, the Cochrane Collaboration requested withdrawal of the review due to the employment of the author. A new protocol for a review to cover this topic will be published. This will have a new title and a markedly improved protocol fulfilling new and important developments and standards within the Cochrane Collaboration as well as an improved inclusion and search strategy making it necessary to embark on a completely new review project.

The editorial group responsible for this previously published document have withdrawn it from publication.

Efficacy and safety of metformin for patients with type 1 diabetes mellitus: a meta-analysis

BACKGROUND

Insulin is an essential therapy for patients with type 1 diabetes mellitus (T1DM). With the progression of the disease, many patients with T1DM may have an increased prevalence of insulin resistance; thus the common standard insulin therapy requires a high insulin dosage (>1 unit/kg/day) and is usually associated with many side effects. Studies have shown that metformin may benefit those insulin-resistant individuals with T1DM. This meta-analysis was performed to provide the evidence of clinical efficacy and safety of metformin in T1DM.

MATERIALS AND METHODS

We conducted a search on Medline, EMBASE, and the Cochrane Library for relevant studies published before May 2014 based on "metformin" and "diabetes mellitus, type 1." The following outcomes were evaluated: hemoglobin A1c (HbA1c), fasting plasma glucose (FPG), lipid metabolism, weight, insulin dosage, hypoglycemia, diabetic ketoacidosis, or gastrointestinal adverse events (AEs). The meta-analysis was performed using Review Manager version 5.2 software (The Nordic Cochrane Centre, Copenhagen, Denmark).

RESULTS

In total, eight randomized controlled trials were included. Metformin was associated with a reduction in daily insulin dosage, body weight, total cholesterol level, low-density lipoprotein level, and high-density lipoprotein level but an increase in risk of gastrointestinal AEs compared with placebo treatment in T1DM patients. No significant difference was found between the metformin group and the placebo group in HbA1c level, FPG level, or triglycerides level. No significant difference was found between the metformin group and the placebo group in the risk of severe hypoglycemia or diabetic ketoacidosis.

CONCLUSIONS

Metformin may decrease the daily insulin dosage, body weight, and lipid levels in T1DM. However, metformin does not increase the incidence of hypoglycemia and ketoacidosis. High-quality, large-sample, and long-term follow-up clinical trials are needed to confirm these conclusions.

Tyrosol, a phenolic compound, ameliorates hyperglycemia by regulating key enzymes of carbohydrate metabolism in streptozotocin induced diabetic rats

The present study was designed to evaluate the effects of tyrosol, a phenolic compound, on the activities of key enzymes of carbohydrate metabolism in the control and streptozotocin-induced diabetic rats. Diabetes mellitus was induced in rats by a single intraperitoneal injection of streptozotocin (40 mg/kg body weight). Experimental rats were administered tyrosol 1 ml intra gastrically at the doses of 5, 10 and 20mg/kg body weight and glibenclamide 1 ml at a dose of 600 μg/kg body weight once a day for 45 days. At the end of the experimental period, diabetic control rats exhibited significant (p<0.05) increase in plasma glucose, glycosylated hemoglobin with significant (p<0.05) decrease in plasma insulin, total hemoglobin and body weight. The activities of key enzymes of carbohydrate metabolism such as phosphoenolpyruvate carboxykinase, fructose-1,6-bisphosphatase and glucose-6-phosphatase were significantly (p<0.05) increased and the activities of hexokinase and glucose-6-phosphate dehydrogenase were significantly (p<0.05) decreased in the liver and kidney of diabetic control rats. Further, antioxidants were lowered in diabetic control rats. A significant (p<0.05) decline in glycogen level in the liver and muscle and glycogen synthase activity in the liver and a significant (p<0.05) increase in the activity of liver glycogen phosphorylase were observed in diabetic control rats compared to normal control rats. Oral administration of tyrosol to diabetic rats reversed all the above mentioned biochemical parameters to near normal in a dose dependent manner. Tyrosol at a dose of 20mg/kg body weight showed the highest significant effect than the other two doses. Immunohistochemical staining of pancreas revealed that tyrosol treated diabetic rats showed increased insulin immunoreactive β-cells, which confirmed the biochemical findings. The observed results were compared with glibenclamide, a standard oral hypoglycemic drug. The results of the present study suggest that tyrosol decreases hyperglycemia, by its antioxidant effect.

The effect of glibenclamide on insulin secretion at normal glucose concentrations

AIMS/HYPOTHESIS

The aim of this study was to investigate the incremental and proportional effect of a sulfonylurea on insulin secretion rates at low, elevated and high blood glucose, using parallel groups with ascending or descending glucose steps to minimise potential biases of a single stepped clamp order.

METHODS

Following 14 days on placebo or glibenclamide (2.5 mg) tablets twice daily, separated by 14 days washout, 19 type 2 diabetic patients had ascending or descending three-step hyperinsulinaemic glucose clamps at 4, 8 and 12 mmol/l. C-peptide secretion was estimated by two-compartment C-peptide deconvolution.

RESULTS

Patients in the ascending glucose steps group (n = 10) had mean (SD) age of 60.3 (6.5) years, BMI of 29.8 (4.9) kg/m(2) and fasting glucose on diet alone of 10.6 (2.9) mmol/l; while those in the descending glucose steps group (n = 9) had mean age of 58.2 (8.0) years, BMI of 30.5 (5.4) kg/m(2) and fasting glucose on diet alone of 9.8 (2.2) mmol/l. The geometric means (95% CI) of C-peptide secretion rates on placebo for glucose at 4.0, 8.0 and 12.0 mmol/l were 63 (46, 86), 143 (105, 195) and 205 (149, 281) pmol/min, respectively. On glibenclamide, this increased by 140 (99, 181), 126 (85, 167) and 158 (117, 199) pmol/min, respectively (p < 0.001 vs placebo). The absolute increment was significant (p < 0.001) and independent of clamp glucose concentration (p = 0.54). The proportional increase was greater at 4 mmol/l: 2.8-fold (2.4, 3.2), compared with 1.8-fold (1.5, 2.0) and 1.7-fold (1.4, 1.9) at 8 and 12 mmol/l, respectively (p < 0.001).

CONCLUSIONS/INTERPRETATION

At low-normal glucose, glibenclamide exerted a disproportionate effect on insulin secretion. This study highlights the risks of hypoglycaemia when aiming for tight glucose control on this agent.

Alteration of glucose lowering effect of glibenclamide on single and multiple treatments with fenofibrate in experimental rats and rabbit models

Objective:

Diabetes mellitus is a syndrome of multiple etiologies. Both type 1 and type 2 diabetes lead to multiple abnormalities of lipid and lipoprotein metabolism. The aim of this investigation was to study the influence of fenofibrate on the blood glucose lowering effect of glibenclamide.

Materials and Methods:

Glibenclamide (0.45, 0.23 mg/kg) and fenofibrate (18.1, 9.38 mg/kg) was treated to normal, diabetic rats, and normal rabbits. Blood samples were collected at various time intervals and were analyzed for blood glucose levels using a glucometer.

Results:

Co-administration of fenofibrate with glibenclamide significantly elevated the blood glucose reduction exhibited by glibenclamide.

Conclusion:

The results obtained from single and multiple dose treatments clearly demonstrated the existence of drug-drug interaction at the dose tested in animal models. Hence, this investigation would serve as a preclinical evidence for the effect of fenofibrate on the therapeutic efficacy of glibenclamide.

Glycemic goals in diabetes: trade-off between glycemic control and iatrogenic hypoglycemia

The selection of a glycemic goal in a person with diabetes is a compromise between the documented upside of glycemic control-the partial prevention or delay of microvascular complications-and the documented downside of glycemic control-the recurrent morbidity and potential mortality of iatrogenic hypoglycemia. The latter is not an issue if glycemic control is accomplished with drugs that do not cause hypoglycemia or with substantial weight loss. However, hypoglycemia becomes an issue if glycemic control is accomplished with a sulfonylurea, a glinide, or insulin, particularly in the setting of absolute endogenous insulin deficiency with loss of the normal decrease in circulating insulin and increase in glucagon secretion and attenuation of the sympathoadrenal response as plasma glucose concentrations fall. Then the selection of a glycemic goal should be linked to the risk of hypoglycemia. A reasonable individualized glycemic goal is the lowest A1C that does not cause severe hypoglycemia and preserves awareness of hypoglycemia, preferably with little or no symptomatic or even asymptomatic hypoglycemia, at a given stage in the evolution of the individual's diabetes.

Sulfonylureas: a new look at old therapy

Sulfonylurea compounds were the first available oral antidiabetic agents and they remain an important tool in our quest for optimal glucose control. The sulfonylureas stimulate the release of insulin from pancreatic β-cells and have a number of extrapancreatic effects, including decreasing hepatic insulin clearance and reducing glucagon secretion in patients with type 2 diabetes. Although these agents have been the mainstay of pharmacotherapy for patients with type 2 diabetes mellitus (T2DM), their safety and clinical utility has been a matter of active debate in recent years, as their use is associated with risks of hypoglycemia and weight gain. We review the discovery and mechanisms of action of sulfonylureas, and the results of clinical trials to provide practical information on the pros and cons of their use in clinical practice. This review addresses advances in our understanding of mechanisms of action of sulfonylurea agents, their efficacy in T2DM, side effects, and impact on cardiovascular disease outcomes.

Molecular dynamic simulations reveal the mechanism of binding between xanthine inhibitors and DPP-4

We apply molecular docking, molecular dynamics (MD) simulation, and binding free energy calculation to investigate and reveal the binding mechanism between five xanthine inhibitors and DPP-4. The electrostatic and van der Waals interactions of the five inhibitors with DPP-4 are analyzed and discussed. The computed binding free energies using MM-PBSA method are in qualitatively agreement with experimental inhibitory potency of five inhibitors. The hydrogen bonds of inhibitors with Ser630 and Asp663 can stabilize the inhibitors in binding sites. The van der Waals interactions, especially the key contacts with His740, Asn710, Trp629, and Tyr666 have larger contributions to the binding free energy and play important roles in distinguishing the variant bioactivity of five inhibitors.

Sulphonylurea monotherapy for patients with type 2 diabetes mellitus

BACKGROUND

Type 2 diabetes mellitus (T2DM) is a growing health problem worldwide. Whether sulphonylureas show better, equal or worse therapeutic effects in comparison with other antidiabetic interventions for patients with T2DM remains controversial.

OBJECTIVES

To assess the effects of sulphonylurea monotherapy versus placebo, no intervention or other antidiabetic interventions for patients with T2DM.

SEARCH METHODS

We searched publications in The Cochrane Library, MEDLINE, EMBASE, Science Citation Index Expanded, LILACS and CINAHL (all until August 2011) to obtain trials fulfilling the inclusion criteria for our review.

SELECTION CRITERIA

We included clinical trials that randomised patients 18 years old or more with T2DM to sulphonylurea monotherapy with a duration of 24 weeks or more.

DATA COLLECTION AND ANALYSIS

Two authors independently assessed the risk of bias. The primary outcomes were all-cause and cardiovascular mortality. Secondary outcomes were other patient-important outcomes and metabolic variables. Where possible, we used risk ratios (RR) with 95% confidence intervals (95% CI) to analyse the treatment effect of dichotomous outcomes. We used mean differences with 95% CI to analyse the treatment effect of continuous outcomes. We evaluated the risk of bias. We conducted trial sequential analyses to assess whether firm evidence could be established for a 10% relative risk reduction (RRR) between intervention groups.

MAIN RESULTS

We included 72 randomised controlled trials (RCTs) with 22,589 participants; 9707 participants randomised to sulphonylureas versus 12,805 participants randomised to control interventions. The duration of the interventions varied from 24 weeks to 10.7 years. We judged none of the included trials as low risk of bias for all bias domains. Patient-important outcomes were seldom reported.First-generation sulphonylureas (FGS) versus placebo or insulin did not show statistical significance for all-cause mortality (versus placebo: RR 1.46, 95% CI 0.87 to 2.45; P = 0.15; 2 trials; 553 participants; high risk of bias (HRB); versus insulin: RR 1.18, 95% CI 0.88 to 1.59; P = 0.26; 2 trials; 1944 participants; HRB). FGS versus placebo showed statistical significance for cardiovascular mortality in favour of placebo (RR 2.63, 95% CI 1.32 to 5.22; P = 0.006; 2 trials; 553 participants; HRB). FGS versus insulin did not show statistical significance for cardiovascular mortality (RR 1.36, 95% CI 0.68 to 2.71; P = 0.39; 2 trials; 1944 participants; HRB). FGS versus alpha-glucosidase inhibitors showed statistical significance in favour of FGS for adverse events (RR 0.63, 95% CI 0.52 to 0.76; P = 0.01; 2 trials; 246 participants; HRB) and for drop-outs due to adverse events (RR 0.28, 95% CI 0.12 to 0.67; P = 0.004; 2 trials; 246 participants; HRB).Second-generation sulphonylureas (SGS) versus metformin (RR 0.98, 95% CI 0.61 to 1.58; P = 0.68; 6 trials; 3528 participants; HRB), thiazolidinediones (RR 0.92, 95% CI 0.60 to 1.41; P = 0.70; 7 trials; 4955 participants; HRB), insulin (RR 0.96, 95% CI 0.79 to 1.18; P = 0.72; 4 trials; 1642 participants; HRB), meglitinides (RR 1.44, 95% CI 0.47 to 4.42; P = 0.52; 7 trials; 2038 participants; HRB), or incretin-based interventions (RR 1.39, 95% CI 0.52 to 3.68; P = 0.51; 2 trials; 1503 participants; HRB) showed no statistically significant effects regarding all-cause mortality in a random-effects model. SGS versus metformin (RR 1.47; 95% CI 0.54 to 4.01; P = 0.45; 6 trials; 3528 participants; HRB), thiazolidinediones (RR 1.30, 95% CI 0.55 to 3.07; P = 0.55; 7 trials; 4955 participants; HRB), insulin (RR 0.96, 95% CI 0.73 to 1.28; P = 0.80; 4 trials; 1642 participants; HRB) or meglitinide (RR 0.97, 95% CI 0.27 to 3.53; P = 0.97; 7 trials, 2038 participants, HRB) showed no statistically significant effects regarding cardiovascular mortality. Mortality data for the SGS versus placebo were sparse. SGS versus thiazolidinediones and meglitinides did not show statistically significant differences for a composite of non-fatal macrovascular outcomes. SGS versus metformin showed statistical significance in favour of SGS for a composite of non-fatal macrovascular outcomes (RR 0.67, 95% CI 0.48 to 0.93; P = 0.02; 3018 participants; 3 trials; HRB). The definition of non-fatal macrovascular outcomes varied among the trials. SGS versus metformin, thiazolidinediones and meglitinides showed no statistical significance for non-fatal myocardial infarction. No meta-analyses could be performed for microvascular outcomes. SGS versus placebo, metformin, thiazolidinediones, alpha-glucosidase inhibitors or meglitinides showed no statistical significance for adverse events. SGS versus alpha-glucosidase inhibitors showed statistical significance in favour of SGS for drop-outs due to adverse events (RR 0.48, 95% CI 0.24 to 0.96; P = 0.04; 9 trials; 870 participants; HRB). SGS versus meglitinides showed no statistical significance for the risk of severe hypoglycaemia. SGS versus metformin and thiazolidinediones showed statistical significance in favour of metformin (RR 5.64, 95% CI 1.22 to 26.00; P = 0.03; 4 trials; 3637 participants; HRB) and thiazolidinediones (RR 6.11, 95% CI 1.57 to 23.79; P = 0.009; 6 trials; 5660 participants; HRB) for severe hypoglycaemia.Third-generation sulphonylureas (TGS) could not be included in any meta-analysis of all-cause mortality, cardiovascular mortality or non-fatal macro- or microvascular outcomes. TGS versus thiazolidinediones showed statistical significance regarding adverse events in favour of TGS (RR 0.88, 95% CI 0.78 to 0.99; P = 0.03; 3 trials; 510 participants; HRB). TGS versus thiazolidinediones did not show any statistical significance for drop-outs due to adverse events. TGS versus other comparators could not be performed due to lack of data.For the comparison of SGS versus FGS no meta-analyses of all-cause mortality, cardiovascular mortality, non-fatal macro- or microvascular outcomes, or adverse events could be performed.Health-related quality of life and costs of intervention could not be meta-analysed due to lack of data.In trial sequential analysis, none of the analyses of mortality outcomes, vascular outcomes or severe hypoglycaemia met the criteria for firm evidence of a RRR of 10% between interventions.

AUTHORS' CONCLUSIONS

There is insufficient evidence from RCTs to support the decision as to whether to initiate sulphonylurea monotherapy. Data on patient-important outcomes are lacking. Therefore, large-scale and long-term randomised clinical trials with low risk of bias, focusing on patient-important outcomes are required.

Hypoglycemia-associated autonomic failure in diabetes

The concept of hypoglycemia-associated autonomic failure (HAAF) in diabetes posits that recent antecedent hypoglycemia, as well as sleep or prior exercise, causes both defective glucose counterregulation (by attenuating the adrenomedullary epinephrine response, in the setting of absent insulin and glucagon responses) and hypoglycemia unawareness (by attenuating the sympathoadrenal, largely the sympathetic neural, response) and thus a vicious cycle of recurrent hypoglycemia. Albeit with different time courses, the pathophysiology of defense against hypoglycemia - no decrease in therapeutic insulin, no increase in glucagon and an attenuated increase in sympathoadrenal activity - is the same in type 1 diabetes and advanced type 2 diabetes. Hypoglycemia unawareness is reversible by 2-3 weeks of scrupulous avoidance of hypoglycemia in most affected patients. The pathophysiology of HAAF in diabetes explains why the incidence of hypoglycemia increases as patients approach the absolute endogenous insulin deficient end of the disease, provides a comprehensive set of risk factors including those indicative of HAAF, and leads logically to the practice of hypoglycemia risk factor reduction. Because of the risk of hypoglycemic mortality, presumably from cardiac arrhythmias, glycemic goals in diabetes should be individualized, based in part on the risk of hypoglycemia. By practicing hypoglycemia risk reduction - addressing the issue, applying the principles of aggressive glycemic therapy and considering both the conventional risk factors and those indicative of HAAF - it is possible to both improve glycemic control and reduce the risk of hypoglycemia in many patients with diabetes.

2-year efficacy and safety of linagliptin compared with glimepiride in patients with type 2 diabetes inadequately controlled on metformin: a randomised, double-blind, non-inferiority trial

BACKGROUND

Addition of a sulphonylurea to metformin improves glycaemic control in type 2 diabetes, but is associated with hypoglycaemia and weight gain. We aimed to compare a dipeptidyl peptidase-4 inhibitor (linagliptin) against a commonly used sulphonylurea (glimepiride).

METHODS

In this 2-year, parallel-group, non-inferiority double-blind trial, outpatients with type 2 diabetes and glycated haemoglobin A(1c) (HbA(1c)) 6·5-10·0% on stable metformin alone or with one additional oral antidiabetic drug (washed out during screening) were randomly assigned (1:1) by computer-generated random sequence via a voice or web response system to linagliptin (5 mg) or glimepiride (1-4 mg) orally once daily. Study investigators and participants were masked to treatment assignment. The primary endpoint was change in HbA(1c) from baseline to week 104. Analyses included all patients randomly assigned to treatment groups who received at least one dose of treatment, had a baseline HbA(1c) measurement, and had at least one on-treatment HbA(1c) measurement. This trial is registered at ClinicalTrials.gov, number NCT00622284.

FINDINGS

777 patients were randomly assigned to linagliptin and 775 to glimepiride; 764 and 755 were included in analysis of the primary endpoint. Reductions in adjusted mean HbA(1c) (baseline 7·69% [SE 0·03] in both groups) were similar in the linagliptin (-0·16% [SE 0·03]) and glimepiride groups (-0·36% [0·03]; difference 0·20%, 97·5% CI 0·09-0·30), meeting the predefined non-inferiority criterion of 0·35%. Fewer participants had hypoglycaemia (58 [7%] of 776 vs 280 [36%] of 775 patients, p<0·0001) or severe hypoglycaemia (1 [<1%] vs 12 [2%]) with linagliptin compared with glimepiride. Linagliptin was associated with significantly fewer cardiovascular events (12 vs 26 patients; relative risk 0·46, 95% CI 0·23-0·91, p=0·0213).

INTERPRETATION

The results of this long-term randomised active-controlled trial advance the clinical evidence and comparative effectiveness bases for treatment options available to patients with type 2 diabetes mellitus. The findings could improve decision making for clinical treatment when metformin alone is insufficient.

FUNDING

Boehringer Ingelheim.

The management of type 2 diabetic patients with hypoglycaemic agents

Type 2 Diabetes Mellitus (T2DM) is characterized by chronic hyperglycemia with disturbance in carbohydrate, lipid, and protein metabolism due to insulin resistance and beta cell dysfunction. Epidemiological studies have confirmed a global pandemic of T2DM, which has created an enormous burden on society, with regard to morbidity, mortality, and health care expenditures. Life style modifications are fundamental not only in early stages of disease management but need to be intensified as disease progresses. United Kingdom Prospective Diabetes Study (UKPDS) has demonstrated the progressive nature of T2DM, and as disease progresses, a combination agents-oral antidiabetic drugs (OAD) and insulin-are needed in order to maintain good sugar control. The general consensus of HbA1c target for most patients is less than 7%, and various guidelines and algorithms have provided guidance in patient management to keep patient at goal. As our understanding of pathophysiological defects advances, targeting treatment at underlying defects not only enables us to achieve HbA1c goal but also reduces morbidities, mortalities, and progression of the disease. Traditional oral agents like metformin and sulfonylureas have failed to arrest the progression of T2DM. New agents such as TZD, DPP-4 inhibitor, and SGLT-2 may increase our armamentariums against T2DM.

Prescription patterns for diabetes mellitus and therapeutic implications: a population-based analysis

OBJECTIVE

To analyze drug prescriptions for insulin and oral antidiabetic drugs in type 1 and type 2 diabetes mellitus patients seen in the Brazilian Public Healthcare System (Unified Health System - SUS) in Ribeirao Preto, SP, Brazil.

SUBJECTS AND METHODS

All the patients with diabetes seen in the SUS in the western district of Ribeirao Preto, SP, Brazil between March/2006 and February/2007 were included in the study.

RESULTS

A total of 3,982 patients were identified. Mean age of the patients was 60.6 years, and 61.0% were females. Sixty percent of the patients were treated with monotherapy. Doses of oral antidiabetic drugs were lower in monotherapy than in polytherapy. Ten patients received doses of glibenclamide or metformin above the recommended maximum doses, and in elderly patients there was no reduction in drug doses.

CONCLUSION

Monotherapy with oral antidiabetic drugs was the predominant procedure, and the doses were not individualized according to age.

Gliclazide does not fully prevent 2-deoxy-D-ribose-induced oxidative damage because it does not restore glutathione content in a pancreatic β-cell line

We compared the effects of gliclazide, an antidiabetic agent with antioxidant properties, and N-acetyl-L-cysteine (NAC), a glutathione precursor, in protecting against 2-deoxy-D-ribose- (dRib-) induced oxidative damage in HIT-T15 cells. Using trypan blue staining and flow cytometry with annexin V/PI staining, gliclazide treatment slightly reversed dRib-induced cell death and apoptosis, and NAC treatment markedly reduced both measures. Likewise, flow cytometry using DHR 123 staining showed that the levels of dRib-induced reactive oxygen species (ROS) were partially suppressed by gliclazide and completely inhibited by NAC. Using electron spin resonance spectrometry, gliclazide and NAC scavenged hydroxyl radicals generated by Fenton reaction to a similar degree in a cell-free system. NAC, but not gliclazide, completely restored the intracellular glutathione depleted by dRib using monochlorobimane fluorescence and glutathione assays. Thus, gliclazide treatment suppressed dRib-induced oxidative damage in HIT-T15 cells less than NAC did because gliclazide did not restore the intracellular glutathione content as effectively as NAC. In addition, the elevation of intracellular glutathione rather than free radical scavenging might be an important mechanism for protecting against dRib-induced oxidative damage in a β-cell line.

Antihyperglycemic, antihyperlipidemic and antioxidative potential of Prosopis cineraria bark

Alloxan administration in male Swiss albino mice, induced diabetes by increasing blood glucose concentration and reducing hepatic glycogen content as compared to normal control group. Besides, serum lipid profile parameters such as total-cholesterol, triglyceride, low-density lipoprotein and very low-density lipoprotein-cholesterol were also elevated, whereas, the level of high-density lipoprotein-cholesterol was reduced significantly (P<0.05) in diabetic mice. Treatment of diabetic animals with crude ethanolic extract of bark of Prosopis cineraria (P. cineraria) for 45 days, significantly lowered blood glucose level, elevated hepatic glycogen content and maintained body weight and lipid-profile parameters towards near normal range. Declined activity of antioxidant enzymes and concentration of non-enzymatic antioxidants were also normalized by drug treatment, thereby reducing the oxidative damage in the tissues of diabetic animals and hence indicating the anti-diabetic and antioxidant efficacy of the extract.

Selection and dosing of medications for management of diabetes in patients with advanced kidney disease

Diabetes mellitus is a leading cause of kidney disease worldwide. A large and expanding array of treatments for diabetes is available to improve glycemic control, including newer classes of drugs, such as thiazolidinediones and incretin-based therapies. The presence of impaired kidney function with reduced glomerular filtration rate should influence choices, dosing, and monitoring of hypoglycemic agents, as some agents require a dosing adjustment in patients with kidney disease and some are entirely contraindicated. This article reviews the clinical use of insulin and other antidiabetic therapies, focusing on pharmacokinetic properties and dosing in patients with advanced kidney disease.

Drugs and pharmaceuticals: management of intoxication and antidotes

The treatment of patients poisoned with drugs and pharmaceuticals can be quite challenging. Diverse exposure circumstances, varied clinical presentations, unique patient-specific factors, and inconsistent diagnostic and therapeutic infrastructure support, coupled with relatively few definitive antidotes, may complicate evaluation and management. The historical approach to poisoned patients (patient arousal, toxin elimination, and toxin identification) has given way to rigorous attention to the fundamental aspects of basic life support--airway management, oxygenation and ventilation, circulatory competence, thermoregulation, and substrate availability. Selected patients may benefit from methods to alter toxin pharmacokinetics to minimize systemic, target organ, or tissue compartment exposure (either by decreasing absorption or increasing elimination). These may include syrup of ipecac, orogastric lavage, activated single- or multi-dose charcoal, whole bowel irrigation, endoscopy and surgery, urinary alkalinization, saline diuresis, or extracorporeal methods (hemodialysis, charcoal hemoperfusion, continuous venovenous hemofiltration, and exchange transfusion). Pharmaceutical adjuncts and antidotes may be useful in toxicant-induced hyperthermias. In the context of analgesic, anti-inflammatory, anticholinergic, anticonvulsant, antihyperglycemic, antimicrobial, antineoplastic, cardiovascular, opioid, or sedative-hypnotic agents overdose, N-acetylcysteine, physostigmine, L-carnitine, dextrose, octreotide, pyridoxine, dexrazoxane, leucovorin, glucarpidase, atropine, calcium, digoxin-specific antibody fragments, glucagon, high-dose insulin euglycemia therapy, lipid emulsion, magnesium, sodium bicarbonate, naloxone, and flumazenil are specifically reviewed. In summary, patients generally benefit from aggressive support of vital functions, careful history and physical examination, specific laboratory analyses, a thoughtful consideration of the risks and benefits of decontamination and enhanced elimination, and the use of specific antidotes where warranted. Data supporting antidotes effectiveness vary considerably. Clinicians are encouraged to utilize consultation with regional poison centers or those with toxicology training to assist with diagnosis, management, and administration of antidotes, particularly in unfamiliar cases.

Killer proteases and little strokes--how the things that do not kill you make you stronger

The phenomenon of ischemic preconditioning was initially observed over 20 years ago. The basic tenant is that if stimuli are applied at a subtoxic level, cells upregulate endogenous protective mechanisms to block injury induced by subsequent stress. Since this discovery, many conserved signaling mechanisms that contribute to activation of this potent protective program have been identified in the brain. A clinical correlate of this basic research finding can be found in patients with a history of transient ischemic attack (TIA), who have a decreased morbidity after stroke. In spite of multidisciplinary efforts to design safer, more effective stroke therapies, we have thus far failed to translate our understanding of endogenous protective pathways to treatments for neurodegeneration. This review is designed to provide clinicians and basic scientists with an overview of stress biology after TIA and preconditioning, discuss new therapeutic strategies to target the protein dysfunction that follows ischemic injury, and propose enhanced biochemical profiling to identify individuals at risk of stroke after TIA. We pay particular attention to the unanticipated consequences of overly aggressive intervention after TIA in which we have found that traditional cytotoxic agents such as free radicals and apoptosis associated proteases is essential for neuroprotection and communication in the stressed brain. These data emphasize the importance of understanding the complex interplay between chaperones, apoptotic proteases including caspases, and the proteolytic degradation machinery in adaptation to neurological injury.

Initial monotherapy with either metformin or sulphonylureas often fails to achieve or maintain current glycaemic goals in patients with Type 2 diabetes in UK primary care

AIMS

To describe initial achievement of glycaemic targets and subsequent hyperglycaemia in patients with Type 2 diabetes managed with oral agent monotherapy in UK primary care from 1998 to 2004.

METHODS

Electronic medical records of patients initiating metformin (n = 3362) or a sulphonylurea agent (n = 3070) in 290 UK primary care practices were retrieved from the General Practice Research Database (GPRD). Patients included had an HbA(1c) recorded 0-90 days before and 90-365 days after initiating monotherapy. The probability of achieving glycaemic thresholds in the first year, and for those achieving such targets, the probability of inadequate glycaemic control (HbA(1c) > 6.5%, > 7.0%, > 7.5%) over time is described.

RESULTS

Low baseline HbA(1c) and drug initiation within 3 months of diabetes diagnosis were the strongest predictors of initial achievement of glycaemic targets. The proportion of patients with diabetes duration > or = 4 months who achieved HbA(1c) < 7% in the first year ranged from 24% to 88% for highest to lowest baseline HbA(1c) category in sulphonylurea initiators and from 19% to 86% in metformin initiators, with slightly higher proportions for newly diagnosed patients. Kaplan-Meier analyses suggested that 55% and 70% of patients who initially achieved glycaemic targets had HbA(1c) measurements above these targets at 2 and 3 years.

CONCLUSIONS

Many patients fail to achieve glycaemic goals with initial monotherapy and, of those who achieve current goals, few consistently maintain these targets over 3 years. Research is needed to evaluate whether more aggressive treatment or alternative treatments can improve the long-term maintenance of glycaemic control in patients with Type 2 diabetes.

Design and synthesis of long-acting inhibitors of dipeptidyl peptidase IV

A series of (4-substituted prolyl)prolinenitriles were synthesized and evaluated as inhibitors of dipeptidylpeptidase IV (DPP-IV). Among those tested, the 4beta-[4-(hydroxyphenyl)prolyl]prolinenitriles showed a potent inhibitory activity with a long duration of action. Metabolic formation of the corresponding phenol glucuronates was found to contribute to their long duration of action. The activity profiles of the synthesized compounds are reported and structure-activity relationships are also presented.

Oral antidiabetic agents as cardiovascular drugs

The increased risk of cardiovascular disease associated with type 2 diabetes is well documented. Lesser degrees of abnormal glucose metabolism including impaired fasting glycaemia and impaired glucose tolerance are also associated with increased cardiovascular risk. Studies showing improved cardiovascular outcomes with oral antidiabetic agents are limited, with the UKPDS demonstrating improved macrovascular outcomes only in a subgroup of obese patients with type 2 diabetes treated with metformin, and the heavily criticized STOP NIDDM trial showing a reduction in the number of cardiovascular events with the alpha glucosidase inhibitor acarbose. In recent years there has been an increase in the number of oral antidiabetic drugs available to treat the hyperglycaemia of diabetes. Some of these drugs have complex metabolic properties, additional to their antihyperglycaemic effect, improving endothelial function and markers of atherogenesis, with the potential to reduce cardiovascular morbidity and mortality, as supported by the recently published results of the PROACTIVE study. The results of further long-term cardiovascular outcome studies with these newer agents are awaited.

Novel 1,3-dicarbonyl compounds having 2(3H)-benzazolonic heterocycles as PPARγ agonists

A series of 1,3-dicarbonyl compounds having 2(3H)-benzazolonic heterocycles has been synthesized and tested for PPARgamma agonist activity. SAR were developed and revealed that 6-acyl-2(3H)-benzothiazolone derivatives with 1,3-dicarbonyl group were the most potent. IP administration of compound 22 exhibited comparable levels of glucose and triglyceride correction to PO administration of rosiglitazone in the ob/ob mouse studies.

Rosiglitazone versus bedtime insulin in the treatment of patients with conventional oral antidiabetic drug failure: a 1-year randomized clinical trial

This study was conducted to evaluate the efficacy and tolerability of rosiglitazone in the treatment of patients with secondary oral antidiabetic drug (OAD) failure and to directly compare its use with bedtime insulin. A total of 112 Chinese patients with type 2 diabetes and conventional OAD failure were recruited. Patients were randomly assigned to treatment with rosiglitazone or bedtime isophane insulin; they continued to take their original oral antidiabetic drugs. Glycemic index, other clinical profiles, and tolerability were assessed during treatment and 1 y after add-on treatment was provided. Among the 112 patients, mean age (+/-SD) was 58.2+/-11.0 y (median, 58 y; range, 37 to 84 y). Both rosiglitazone (n=56) and insulin (n=56) significantly improved fasting glucose (2.4 and 3.7 mmol/L, respectively) and hemoglobin A1c concentrations (1.1% and 1.3%, respectively). Both therapies increased body mass index after 1 y of treatment (0.9 and 0.8 kg/m2, respectively). Only rosiglitazone increased high-density lipoprotein cholesterol concentrations (0.1 mmol/L). Four patients (7.1%) who were given rosiglitazone developed adverse effects (2, ankle edema, and 2, gastrointestinal disturbance). Six insulin-treated patients (10.7%) described adverse effects (5, early morning hypoglycemia, and 1, anxiety). Investigators concluded that in Chinese patients with type 2 diabetes and secondary conventional OAD failure, 1 y of treatment with rosiglitazone or bedtime insulin added to the regular regimen resulted in similar improvements in glycemic control. Rosiglitazone was also associated with improved high-density lipoprotein cholesterol levels. The addition of rosiglitazone may offer a safe and effective alternative to bedtime insulin treatment.